Center-rest for lathes.



PATENTED NOV. 1, 1904.

O. E. MASTERMAN.

CENTER REST FOR LATHES.

APPLICATION FILED APR.'11;1904.

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Zz'fnesses PATENTED NOV. 1, 1904.

O. E. MASTERMAN.

CENTER REST FOR LATHES.

APPLICATION FILED APR.11,1904.

N0 MODEL.

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UNITED STATES Patented November 1, 1904-.

OGTAVIUS E. MASTERMAN, OF ALLEGHENY, PENNSYLVANIA.

CENTER-REST FOR LATHES.

SPECIFICATION forming part of Letters Patent No. 773,957, dated November 1 1904.

Application filed April 11, 1904.. Serial No. 202,535- (No model.)

To rt whom it inrty concern:

Be it known that I, OCTAVIUS E. MASTER- MAN, of the city of Allegheny, county of Allegheny, and State of Pennsylvania, have invented a new and useful Improvement in Cen ter-Rests for Lathes, of which the following is a specification.

The object is to provide a practical universal center-rest from which the work may be easily and quickly removed without disturbing the adjustment of the jaws.

My invention, generally stated, consists in a standard supported upon the body of a lathe and having radially-moving jaws moving simultaneously one with the other by means of certain mechanism to be hereinafter more fully described. The guides for said jaws are arranged in two sections of the carrying-frame, one above and two below, said carrying-frame being longitudinally divided and so hinged that the upper half may be swung out of the way of the work and the work be easily and quickly removed therefrom.

I will now describe my invention, so that others skilled in the art may make and use the same, reference being had to the accompanying drawings, in which Figure 1 is a front elevation, partially in section, showing my improved device. Fig. 2 is avertical section on the line II II of Fig. 1. Fig. 3 is a plan view of the jaw and guide; and Fig. I is a sectional view on the line IV IV, said section being developed into a plane.

Like symbols of reference indicate like parts wherever they occur.

In the drawings, 2. represents the body of the center-rest supported upon the standards 3, by means of which said center-rest may be secured to a lathe in the usual manner. The body or casing is formed in two parts or segments, the upper segment being hinged to the lower segment, as shown at 4:, and the two segments being fastened by means of a hinged lever 5, said lever having a nut 6 threaded thereon for the purpose of drawing the two segments into perfect engagement. Attached to these segments or formed integral therewith are radial guides 7, two of which are secured in the lower segment and a third in the upper segment. These guides serve to hold in place the jaws 8, which are moved to and from the center by means of the worms 9, which engage the teeth of the rack 10, cut into the rear faces of said jaws. Said worms 9 are mountedupon the spindles 11, which have squared ends for engagement of a key, by which they may be rotated for the purpose of imparting said radial movement to the jaws 8. Also mounted upon the spindles 11 are the pinions 12, which engage with a circular rack 13, said rack being guided in the casing. This rack 13 is composed of two segments, the di vision between said segments being shown in the drawings by the lines 14. It will be readily understood that by rotation of any one of the spindles 11 the movement will be imparted through the pinions 12 to the circular rack 13, which in turn will impart a similar movement to the other shafts, and the jaws 8 will all move in unison. The purpose of this circular rack being formed in two segments is to have a segment retained in each half of the casing when said casing is opened for the purpose of removing or inserting the work to be operated upon. It will be necessary, however, for the divisional line of these segments to coincide with the division in the casing when said parts are to be opened. For this purpose I have arranged the spring-pressed plunger 15, the lower end of said plunger being pointed to engage a notch 16 in one of the segments of the rack. In removing the work it will only be necessary to operate one of the spindles 11 until the spring-pressed plunger 15 is seen to drop into the notch 16, which indicates that the two segments of said circular rack are then in such position that the casing may be opened.

After the jaws 8 have been set at the proper position to support the work they may be secured in said position by means of the setscrew 17, which may be turned into engagement with the rack 13 and prevent any move ment of said rack, and consequently of the aws.

The jaws 8 may be formed'at one end with a projecting lug 18 for the purpose of engaging the interior of atube or any work of hollow design, and said tube may thus be centered while operating upon the surface of the l same. These jaws 8 may be made so that both ends of said jaws may be used to engage the work by merely inverting the same in their guides.

For the purpose of gaging the diameters at which the jaws 8 are set I provide upon one of the guides graduated plates 19 and 20, the one for outside diameters and the other for gaging the inside diameters of the work. These plates are preferably made adjustable by means of the set-screws 21, operating in slots 22, formed in said plates, and by this means the plates may be adjusted so that the opening of the jaws 8 will be more accurately registered.

' The operation of my device is as follows: The jaws 8 are operated by shafts 11 by means ofa key in thehands of the operator until the two segments of the circular rack 13 are in such position that the parts of the casing may be opened,which position willbe indicated by the dropping of the spring-pressed plunger 15, as previously described. The casing is then opened and the work is inserted in the lathe. The casing is then closed and the two parts locked in position. This opening of the casing will be arranged, preferably, at the fullest extent or diameter of the movement of the jaws 8, so that Work of any size may be easily inserted. After the work has thus been placed in the latheand the casing secured in place the jaws may be moved toward each other to the proper position for supporting the work by means of a key in the hands of the operator, as has been previously described, the spindles 11, carrying the worms 9, and the pinions 12 being rotated by the operator, the jaws 8 being moved inward radially by means of the worms 9 engaging with the teeth of the rack upon the rear faces of said jaws, and the movement being imparted by means of the pinions 12, through the circular rack 18, to all the jaws in a similar manner. The rack is so guided in the casing that the two parts of same fit snugly one against the other, thus eliminating any possible lost motion in said halves.

It is often necessary to adjust the jaws separately on account of the uneven wear thereof, which would thus throw them out of center. When it is found that one or more of the jaws have been so worn as to throw the jaws out of center with the other jaws, it will be only necessary to remove the back plate 23, remove the rack 13, so that the movement of one jaw will not be imparted to any of the other jaws, and then each jaw is separately adjusted to an arbor, which may be centered in the chuck of the lathe. After each jaw has thus been adjusted the rack 13 is put back in place and the back plate 23 replaced, after which the gages 19 and 20 are adjusted to zero.

It is easily seen that by my construction the opening and closing of the casing will positively eliminate any tendency of the jaws to move out of adjustment the one with the other.

I do not wish to limit myself to the exact details of construction herein shown and described, as it is evident that certain details may be changed without departing from the spirit of my invention.

Having thus described my invention, what I claim, and desire to secure by Letters Patent, is

In a center-rest for lathes, the combination of a standard supporting a divided guide-ring, radial arms on said ring, movable jaws guided therein, rack-teeth upon the face of said jaws, spindles mounted in said radial arms, each of said spindles carrying a worm in engagement with said rack-teeth, pinions on each of said spindles, said pinions being adapted to engage a diametrally-divided, circular rack, to impart a universal movement to the jaws, the division of said circular rack being adapted to register with the diametral division of said circular guide, substantially as and for the purposes set forth.

In testimony whereof I have hereunto set my hand.

OCTAVIUS E. MASTERMAN.

\Vitnesses:

A. M. STEEN, WALTER FAMARIss. 

